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Effect of two sous-vide cooking methods
on fatty acid composition and oxidative
stability of longissimus thoracis muscle
from pigs receiving a diet containing or not
extruded linseed
Anna Maria Belmonte1, Corina Scutaru1, Giovanna Minelli1,2, Paolo Macchioni3, Luisa Antonella Volpelli1,2, Domenico Pietro Lo Fiego1,2
1Dipartimento di Scienze della Vita, University of Modena
and Reggio Emilia, Italy
2Centro per il Miglioramento e la Valorizzazione delle Risorse
Biologiche Agroalimentari, University of Modena and Reggio Emilia, Italy
3Dipartimento di Scienze e Tecnologie Agro-Alimentari, Alma
Mater Studiorum University of Bologna, Italy Contact: [email protected]
To verify the effects of two different sous-vide cooking conditions on lipid oxidation and fatty acid (FA) composition of longissimus thoracis (LT) muscle, 24 pigs, evenly divided into two groups of 12 subjects each, were used. One group received a barley-soya bean meal diet (C) and the second was given the same feed where 5% of extruded linseed partly replaced barley, to obtain a n-3 FA enriched diet (L). At slaughter, from each left half carcase, two samples of LT muscle were collected, packed under vacuum and stored at −18 °C until analysis. The samples were cooked in water bath according to two different methods: at high temperature (80 °C) and short-time i.e. samples left until the core temperature reached 70 °C (A); at low temperature (60 °C) and long-time (15 h) (B). After cooking, the samples were refrigerated (2 °C) for 24 h. Oxidative stability was measured by a dosage of the 2-thiobarbituric acid reactive substances (TBARS) content, expressed as milligrams of malondialdehyde (MDA)/kg of meat, and FA composition was determined by capillary gas chromatography. The content of each fatty acid is expressed as a percentage
of the total FAs detected. The statistical analysis was performed by means of ANOVA, using the GLM procedure of SAS. Dietary treatment (C vs. L) and cooking condition (A vs. B) were used as independent variables. The different sous-vide cooking conditions affected neither lipid oxidation nor FAs percentage of LT
muscle. Extruded linseed feeding brought about an increase of the percentage of total n–3 FA (2.67 vs. 0.98; p<.01) and also of polyunsaturated fatty acids (12.02 vs. 9.68; p<.01) in intramuscular
fat but did not affect lipid oxidation. This enabled to obtain pork with a more favourable n–6/n–3 ratio (3.68 vs. 10.42 in L and C group, respectively; p<.01), according to the global health guidelines. Thus, an enriched linseed diet ameliorates the FA composition of pork. The effect of the two different sous-vide cooking methods on lipid composition and oxidative stability of pork does not differ, irrespective of dietary treatments.
Acknowledgements
The research was funded by POR FESR Emilia Romagna 2014–2020 [PG/2015/730542 – ‘Innovare la filiera suina mediante la valorizzazione di sottoprodotti vegetali e l’impiego di avanzate tecnologie “omiche” e di processo, per la produzione sostenibile di carne e salumi ad impatto positivo sulla salute’].
